BACKGROUND AND AIMS: Transient elastography is increasingly being used in patients with chronic liver disease. It has proven particularly useful to identify patients with advanced fibrosis or cirrhosis, while classification of no or little fibrosis appears to be difficult. In general, stiffness values <6 kPa are considered normal, whereas patients with higher levels are candidates for a disease-specific treatment or further diagnostic evaluation. Parameters influencing liver stiffness may include food intake that increases liver blood flow. METHODS: In a pilot study, transient elastography was performed in eight patients with chronic hepatitis C at fasting and serially for 180 min after intake of a standardized breakfast. Confirmatory, 56 patients and 19 controls underwent liver stiffness determination at fasting, directly after meal intake and 1 h after breakfast. RESULTS: Liver stiffness significantly increased immediately after food intake for up to 60 min (P=0.01) before normalizing after 180 min. An intraindividual analysis showed a significant increase in 22 out of 43 patients with an initial liver stiffness <or=10 kPa. An increase of at least 1 kPa after food intake was found in 24 out of 43 (56%) patients with initial stiffness <or=10 kPa. Notably, nine out of 23 (39%) patients with normal initial liver stiffness (<6 kPa) had a value of >6 kPa after food intake, potentially leading to unnecessary treatment or diagnostic procedures. CONCLUSION: Food intake increases liver stiffness in patients with hepatitis C virus infection and healthy controls. To standardize liver stiffness evaluation, we suggest measurement in the fasting condition.